As Eugene writes below, today's decision in Murthy v. Missouri does not tell us much about the very important First Amendment questions argued to the Court. But it does tell us some useful things about standing doctrine and the role of the Supreme Court.

The Court (in an opinion by Justice Barrett) reversed the Fifth Circuit, and refused to reach the merits, on the grounds that the plaintiffs had not adequately shown that their rights were implicated by the resolution of the case—i.e., because they had not shown "standing" to sue and thus the Court was not confronted with a "case" or "controversy" as the Constitution requires.

While Justice Barrett's opinion is long, it has two important overarching points.

Read more at The Volokh Conspiracy